Glossary:anneal: The heating process by which the gamma sensor head is heated and reset. Data taken during anneals are marked as bad data.
bad codes: Data which is suspect or known bad will have a value greater than 0 in the bad_code or bad_flag column (field) during a specific range. Data may be flagged bad due to known hardware changes, gain changes, or other factors.
bad data: See bad codes.
calibrated data: See calibrated products.
calibrated products: Calibrated products, or data, have been run through an extensive process to calibrate and correct the data to a common energy scale, or have been corrected in other ways. For example, the Corrected Gamma Spectrum (CGS), or calibrated gamma spectra, are corrected for gain, offset and linearity. All the corrected spectra have a common energy scale, which allows the direct comparison of individual spectra as a result of the corrections.
CEB: See Central Electronics Box.
Central Electronics Box: The electronics device shared by the three Gamma-Ray Spectrometer instruments.
CEB time: The current time of the electronic clock of the Central Electronics Box.
Channelized Data: Channelized Data are engineering data that may be changed only by JPL personnel for spacecraft controls. Some GRS engineering decisions depend on this type of data, but not vice versa. Channelized values are different than other engineering values, in that they are recorded by the spacecraft computer and are received and processed by JPL, and then ingested into the University of Arizona's Gamma-Ray Spectrometer database.
Command List Data: Command List data are records of the commands issued to the File Interchange System (FIS) for up-link to the spacecraft and executed by the CEB.
Corrected Gamma Spectra (CGS): The Mars Odyssey Gamma Ray Spectrometer Corrected Gamma Spectra (CGS) data set is a time series collection of corrected gamma spectra measurements from the Gamma Subsystem (GS) which are all recalculated to a common energy scale.
Derived Neutron Data (DND): The GRS Derived Neutron Data (DND) data set is a time series collection of derived neutron data measurements from the Neutron Spectrometer (NS) sub-system of the Mars Odyssey Gamma-Ray Spectrometer. The Derived Neutron Data are an intermediate data product. Raw data are processed, then the neutron data is derived from it. Finally, a set of calculations can be run that will result in thermal, epithermal, and fast neutron fluxes.
E Kernel Data: E-Kernel (or Experiment Kernel) data consists of the Experimenter's Notes, the list of commands sent, and the associated timing information. These data are produced in response to a set of commands being placed on the File Interchange System (FIS).
Engineering Data: Engineering Data are specific monitoring values recorded by the Gamma-Ray Spectrometer's Central Electronics Box (CEB). Engineering Data are records of temperatures and other parameters which are used to assess health of the gamma-ray spectrometer's instruments. These data are also used during the calibration of data to common energy scales.
File Interchange System (FIS): The File Interchange System Tool is an automated process that allows a user to submit commands, files, and experiment kernels (E-Kernel) to the FIS for upload to the spacecraft and to the University of Arizona's GRS database for record keeping. The FIS tool uses JPL-supplied tools to create full Spacecraft Activity Sequence Files (SASFs) and place them in the FIS. It is command-line driven to allow batch processing and simple terminal access. A Graphical User Interface (GUI) is also available to allow browsing of input files and creation of the E-Kernel.
Gamma Spectra, Uncorrected: The uncalibrated gamma spectra data, or "raw" gamma spectra, are composed of the raw, uncorrected gamma spectra obtained by the Gamma Subsystem (GS) which includes associated timing and spatial information.
Gamma Subsystem: One of the three Gamma-Ray Spectrometer instruments. The Gamma Subsystem obtains raw (uncalibrated) gamma data.
Gamma Sensor Head: See Gamma Subsystem.
HEND Spectra: High-Energy Neutron Detector (HEND) spectral data is raw (uncorrected) data obtained by the High-Energy Neutron Detector instrument, and consists of HEND records and associated timing and spatial information. HEND records are also called frames.
High Energy Neutron Detector (HEND): One of the three Gamma-Ray Spectrometer instruments. This detector obtains raw HEND data.
LANL: Los Alamos National Laboratory.
LANL data: See Neutron Spectra.
LPL: The Lunar and Planetary Laboratory. LPL is located on the main University of Arizona campus in Tucson, Arizona.
: Solar longitude in the orbit of Mars around the Sun. This is a time period, usually measured in the Data Interface as 15 degrees of solar longitude for the planet of Mars. 15 degrees of is equivalent to half a Martian season.
Message Log Data: The Message Log data are messages returned from the Gamma-Ray Spectrometer's Central Electronics Box (CEB). When the CEB receives a command, it either sends a reply equivalent to "I understand" or returns an error message. For this reason, this type of data is sometimes called "Message and Error" data as both are recorded.
Neutron spectra: Uncalibrated, or raw, neutron spectra are obtained by the Neutron Spectrometer instrument and consist of fifteen histograms, event data, and associated timing and spatial information. The neutron event data consists of the cumulative counts of neutrons detected at one of four prisms over a collection interval. Neutron spectra are also called "LANL data."
Neutron Spectrometer (NS): One of the three Gamma-Ray Spectrometer instruments, the Neutron Spectrometer collectes neutron spectra.
pixel: A data collection interval, or pixel, is approximately 19.7 seconds in length, but can vary over the course of mapping. This is a much different definition for the word "pixel" than is used in image processing, traditional image manipulations, or visual camera terminology, where a pixel (or picture element) is equal to the smallest discrete component of an image or picture on a CRT screen (usually a colored dot). In this case, a pixel is a geographic region of the planet's surface over which the instruments have collected data (spectra) for the approximate interval.
Profile Spectra: Profile Data is comprised of raw (uncorrected) information about gamma-ray bursts as detected by the Gamma-Ray Spectrometer's Gamma Subsystem (GS). These data are used by astrophysicists in conjunction with Gamma-Ray Burst (GRB) data from other spacecraft and Earth-based instruments to locate and study these phenomena. Gamma-ray bursts originate from deep space from astrophysical and stellar phenomena, therefore this type of data is not used to study the planet Mars.
Pulser Spectra: Pulser data are internal GS calibration data, used for data processing and correction. The Pulser Spectra data are time series records taken over the course of a day. Data files are labeled with the date. Individual records are a single data collection interval, which lasts approximately 20 seconds.
Summed Gamma Spectra (SGS): Gamma spectra are summed because an individual gamma spectrum taken over a pixel (a collection interval of about 19.7 seconds) does not contain enough counts to be statistically significant. Individual spectra over a particular time period may be summed on the fly over 5-degree by 5-degree latitude-longitude cells, and the date range will be adjusted to a time period of 15 degrees of solar longitude (). Once data has been summed, it may be used for scientific data analysis.
Uncalibrated Products: Uncorrected data. In the case of gamma spectra, this is data which has not been corrected to a common energy scale, for example.